$\dfrac{17}{10} + \dfrac{20}{100} = {?}$
Explanation: The fractions must have the same denominator before you can add them. Rewrite $\dfrac{17}{10}$ as $\dfrac{170}{100}$ $\dfrac{170}{100} + \dfrac{20}{100} = {?}$ $ = \dfrac{190}{100}$